Barack Obama got exactly zero bounce from his new running mate, Joe Biden, according to a surprising new poll released yesterday – three days after the selection.

In fact, John McCain leads in the Gallup Poll, 46 to 44 percent – the Republican candidate’s best showing in almost three months.

Although McCain’s lead still falls within the poll’s margin of error, the numbers are a worry for Obama supporters who were counting on Biden’s selection as running mate – and the Democratic convention this week – to give them momentum.

“We’ve been waiting to see if there is a bounce for Barack Obama, and we have not seen it yet,” Gallup Poll editor Frank Newport said. “It may take a few days for the convention effect to percolate through to the American public.”

McCain wasted no time trying to capitalize on his narrow lead by blasting Obama on foreign policy. The Republican senator criticized Obama for equating the US “liberation” of Iraq from tyrant Saddam Hussein with Russia’s invasion of “democratic” Georgia.

Obama had said Russia “can’t charge into other countries,” but added: “Of course, it helps if we are leading by example on that point.”

McCain, appearing before the national convention of veterans of the American Legion in Phoenix, said Obama was clearly referring to America’s invasion of Iraq that toppled Saddam.

“If he really thinks that, by liberating Iraq from a dangerous tyrant, American somehow set a bad example that invited Russia to invade a small, peaceful and democratic nation, then he should state it outright – because that’s a debate I welcome,” McCain said to applause.

Obama chided McCain for questioning his “love of country,” and called McCain’s remarks “detestable.”

Though he didn’t comment on the new poll, Obama acknowledged the difficulty of his challenge while campaigning at an American Airlines repair facility in Kansas City. “This is gonna be a close election,” he allowed. “Republicans are gonna make it out as if I’m a scary guy, I’m gonna tax you to death. You don’t know whether I can be trusted.”

He said he didn’t want the election to be about himself – something McCain has tried to engineer through blistering ads. “It’s about you. It’s about who’s gonna be fighting for you,” Obama said.

Candidates usually enjoy a small, though short-lived, bounce after naming a running mate. John Kerry gained four points by picking John Edwards in 2004 and Al Gore gained five points by pairing up with Joe Lieberman in 2000.

On the GOP side, George W. Bush gained three points after selecting Dick Cheney in 2000 and Bob Dole got nine points after his pick of Jack Kemp in ’96.

But Obama’s numbers actually went down.

In the three days immediately before and after Saturday, when Obama selected Biden as his running mate, Obama lost two points, according to the poll.

Democratic consultant Mark Melman said the electorate is too polarized for sudden shifts.

“People who are looking for bounces these days are making a mistake,” Melman said. “When McCain names a vice president, I don’t think he will get a big bounce either.”

Until then, Democrats are hoping that convention speeches by Michelle Obama, Ted Kennedy, Hillary Rodham Clinton and Barack Obama are enough to raise the numbers by the end of the week.

Pollsters are also paying close attention to swing states.

A Quinnipiac University poll released yesterday shows Obama with slight leads in two of three crucial states.

In Florida, McCain leads among likely voters, 47 to 43 percent. Just four weeks ago, Obama was leading there. In Ohio, Obama is leading 44 to 43 percent, a narrower margin than he enjoyed last month. And, in Pennsylvania, Obama leads 49 to 42 percent, a figure unchanged since July.

But House Speaker Nancy Pelosi said Obama is being short-changed by the polls. She said many of the young people attracted to Obama’s campaign are first-time voters who rely on cellphones not targeted by the number-crunchers.

“These are polls of likely voters,” Pelosi said. “Likely voters are people who have voted in the last two elections, and they are likely to vote again. They are not the universe of people who will vote on Nov. 4.”

Biden, meanwhile, got teary-eyed while thanking members of his Delaware delegation.

“I just want you to know that this is a great honor,” Biden said in Littleton, Colo. “It’s a great honor to be nominated vice president of the United States, and it is an honor. And I’m proud of it, and I don’t mean in any way to diminish it.

“But it pales in comparison to the honor I’ve had representing you,” he said before choking up.